trastuzumab emtansine (t-dm1) in her2-positive breast cancer patients with progressive disease after tkis or hp therapy

Conditions: Advanced Breast Cancer; Objective Response Rate; Trastuzumab Emtansine

Summary: the goal of this clinical trial is to learn about the efficacy and safety of trastuzumab emtansine (t-dm1) in the treatment of patients with advanced her2-positive breast cancer after tkis or hp therapy. the main questions it aims to answer are: * the objective response rate of patients receiving t-dm1 therapy with advanced her2-positive breast cancer after tkis or hp therapy. * the adverse events and prognosis of patients with advanced her2-positive breast cancer who receive the t-dm1 therapy. * changes of anti-tumor immunity during t-dm1 therapy in patients with advanced her2-positive breast cancer. participants will receive t-dm1 treatment (3.6mg/kg, d1/21, ivd) until progressive diseases or intolerable adverse effects occurs.


Eligibility criteria:
inclusion criteria: * age ≥ 18 years; pregnancy test (-) for premenopausal and perimenopausal patients, promising to use reliable contraception during treatment. * patients who were be diagnosed with invasive breast cancer according to the eighth edition of american joint committee on cancer (ajcc) staging system, and develop disease progression after anti-her2 therapy (tkis) for stage iv disease at initial diagnosis or within one year of adjuvant anti-her2 therapy (hp) after surgery for early breast cancer. * at least one measurable lesion according to recist 1.1. * ecog score of 0 or 1. * the organ function is still good and meets the following indicators: hemoglobin ≥ 90g/l, white blood cell ≥ 3.5×10\^9/l, platelet ≥ 100×10\^9/l, neutrophil ≥ 1.5×10\^9/l, aspartate aminotransferase or alanine aminotransferase ≤ 3×uln, total bilirubin ≤ 1.5×uln, serum creatinine value ≤ 1.5×uln. * without myocardial ischemia in ecg. * nyha grade i; echocardiography lvef ≥55%; cardiac markers: cardiac troponin (ctni) and brain natriuretic peptide (bnp) within normal range. * complete all necessary baseline laboratory and radiological tests prior to treatment. * complete clinical data. exclusion criteria: * male breast cancer or inflammatory breast cancer. * patients who have other malignant tumors or have contracted malignant tumors other than breast cancer in the past 5 years, except for basal cell carcinoma of the skin or flat cell carcinoma and carcinoma in situ of the cervix that have been adequately treated and controlled. * accompanying other anti-tumor treatments or participating in other clinical trials. * serious diseases that will affect the patient's compliance or put the patient at risk. * major surgical procedures performed within 4 weeks prior to the commencement of study treatment or anticipated major surgical procedures during the course of the study. * patients who have used adc drugs at present or before this study. * history of allergic reactions or contraindications to use of any drug ingredient in this study. * patients with chronic diarrhea and intestinal obstruction, as well as other diseases that affect drug administration and absorption. * patients who have clinical cardiac symptoms or diseases that are not well controlled, such as: heart failure above nyha 2; unstable angina; myocardial infarction occurred within one year; clinically significant supraventricular or ventricular arrhythmias requiring treatment or intervention. * dementia, intellectual abnormality, or any mental illness that interferes with the understanding of informed consent.